The Great Kobuk Sand Dunes of the Kobuk Valley National Park in
northwestern Alaska (67° 07.636' N, 159° 02.371' W) were surveyed for
lichens in August of 1999 and 2000. These 62 sq.km sand dunes are
located in the Kobuk River valley about 160 km east of the town of
Kotzebue, Alaska and the Chukchi Sea. Annual precipitation and
frost-free days at the sand dunes, nearby sub-arctic forests and
tundra average 203mm and 70 days, respectively. The sand dunes were
created during the late Pleistocene and consist of calcareous sands
eroded from the Brooks Range by glaciers and transported to their
present location by the Kobuk River and wind. Much of the material has
been stabilized by vegetation and the remaining active dunes are now
separated from the Kobuk River by coniferous forest. At the perimeter
and within the active dunes area, vegetation islands in various stages
of succession and soil stabilization can be found. To examine lichen
communities characteristic of the various successional stages,
monitoring plots were located on a gradient of weakly stabilized sand
to fully forested habitats. Lichens identified from the sand dunes and
surrounding habitats comprise 63 genera and 160 species, many with
circumpolar arctic-alpine and Amphi-Beringian distributions. Results
from this research will assist the US National Park Service in the
development of dune conservation strategies and visitor-use
regulations, and contribute to the knowledge of the cryptogamic flora
of the Beringian region.